A way To Save Charging Time

[daletournier]

Originally Posted by mrm

Did some further research and it appears that while the linear current taper approximation was indeed too crude, I wasn't too far off in my estimates. Using current taper curve from Fig. 1. here: Charging Information For Lead Acid Batteries – Battery University I did some quick spreadsheet math. Results are attached. My conclusion is that if you extend generator run time to cover the first hour of acceptance phase, solar will cope with the rest. The values in 'Ah' column were calculated using trapeze integration method. If you want to have even better precision you can integrate the included fit function. I didn't see a need for that.

My life just isnt this complicated :-)

[Sailmonkey]

Originally Posted by daletournier

My life just isnt this complicated :-)

Mine can be at times....but not for golf cart batteries!

[daletournier]

Originally Posted by Sailmonkey

Mine can be at times....but not for golf cart batteries!

Lol :-)

[mrm]

Originally Posted by daletournier

Lol :-)

Hey, it was just a fun exercise, nothing complicated

[daletournier]

Originally Posted by mrm

Hey, it was just a fun exercise, nothing complicated

Only joking, all good and I think your smarter than me :-)

[motion30]

I read these posts with great interest and they tend to get very complicated ,but the bottom line is especially on a sailboat install as many panels as you practically can or as many panels as you can afford nobody ever complains they have too much solar

[Paul L]

Originally Posted by Kenomac

Some of these mysteries now have numbers.

During the day with only the stereo turned on the drain is 1.5Ah, when the freezer compressors turn on with the associated water pump, the drain increases to a total of 11Ah on the meter for 10 minutes, then drops back to 7Ah. The fridge draws 3Ah on start up, then drops back to 2Ah. When both units are running at the same time, the total draw is 9Ah continuous after they settle in when combined with the stereo.

The fridge runs 5-6 hours per day (24hrs) and the freezer 4-5 hours per day. Each runs at least 3-4 hours during the daylight hours, less at night.

It's beginning to look like our boat is more energy efficient that I thought, although the energy consumption will certainly increase by 50% during the hot summer months.

Another Solbian factory direct quote just arrived in at €2500 for 450w excluding installation, which I think we can handle ourselves.

That's about 4 to 5 times the price of cheap panels. Hard to justify.

[a64pilot]

Originally Posted by Kenomac

Today's amp burn was 70 amps over a nine hour period. Fridge, freezer, iPad and stereo.

Now I'm going to run the generator for an hour while I cook dinner and see where I'm at.

70 AH in 9 hours is real close I believe to my 100 every 12.
Of course that amounts to 200 AH per 24 hours period.
My Kilowatt of Solar won't replenish that, however I believe that I have one or high resistance connections cause I left them open and unconnected for a couple of years until I finally got around to finishing my Solar install.
Now it's my understanding that ANY regular battery monitor has to be regularly calibrated, that they all wander out of calibration from day one, longer time of course the further out they get. The only exception to that is a Smart Gauge, which supposedly gets more accurate over time, however mine seems spot on right from the beginning, and seems spot on now. Being an AGM bank, the only way I know to tell I'm fully charged is by watching acceptance rate, when it hits .5% at absorption voltage, I'm charged.
You have a flooded bank and can therefore take Specific Gravity readings and tell.
I'd say next time your on Shorepower you need to charge at absorption voltage until SG says your full and then go from there.
I still think your bank could just be in much better shape than you think and it could just be a incorrectly programmed monitor, however if you don't correct it and start really topping off your batteries, it will become damaged of course.

On edit, go with the 450, you will not regret doing so

[mitiempo]

Originally Posted by a64pilot

....... could just be a incorrectly programmed monitor, however if you don't correct it and start really topping off your batteries, it will become damaged of course.

No, it won't damage the monitor. Where did you get that idea?

[Kenomac]

Originally Posted by mitiempo

No, it won't damage the monitor. Where did you get that idea?

He's referring to the batteries becoming damaged.

[a64pilot]

I meant batteries, sorry I'm not real clear at times.
It should have been they

[Kenomac]

Originally Posted by Paul L

That's about 4 to 5 times the price of cheap panels. Hard to justify.

High quality small flexible panels cost more.

[StuM]

Originally Posted by Kenomac

My best guess is 80-100Ah during the day. I'll turn off the shore power first thing tomorrow morning after breakfast and have an answer tomorrow night. I'll have a six hour number for you in about... six hours.

In that case, a solar bank producing 80-100Ah will do little or nothing to top off your batteries. They will still be in whatever state they were when you finished your morning generator run.

That will mean that you rarely if ever reach 100% SOC and your batteries will suffer as a result.

[a64pilot]

Originally Posted by StuM

In that case, a solar bank producing 80-100Ah will do little or nothing to top off your batteries. They will still be in whatever state they were when you finished your morning generator run.

That will mean that you rarely if ever reach 100% SOC and your batteries will suffer as a result.

No,
He runs a big generator twice a day for them to cook, the generator should help again in the afternoon.
However you look at it, he will be in better shape than with no Solar, just I think ideally he needs more that 450W, but certainly understand he doesn't want to spoil the looks of an Oyster.

[Kenomac]

Originally Posted by StuM

In that case, a solar bank producing 80-100Ah will do little or nothing to top off your batteries. They will still be in whatever state they were when you finished your morning generator run.

That will mean that you rarely if ever reach 100% SOC and your batteries will suffer as a result.

We'll still need to run the generator 1/2 hour in the morning and again for 1/2 hr at night to make hot water. During that time the new charger should dump most of the bulk charge back into the bank.

Unlike before, now with the electric cooking going on, the charger is still able to put in 60-80 Ah. Before the additional charger, it would read zero or a negative number while cooking.